Central Iowa Middle School Math Teachers' Circle

Contact us

Elgin Johnston
396C Carver Hall
Iowa State University
Ames, IA 50011

515-294-0302

ehjohnst@iastate.edu

CIMSMTC is partially funded by the Iowa Mathematics and Science Education Partnership
Grant # IMSEP13-08-08
in conjunction with
Iowa State University

Play with these...

Alice is one penny short

of the amount needed to buy a candy bar, and Bob is one dollar short. When they pool their money they still cannot afford the candy bar. What is the price of the candy bar?

You have a collection

of several tiles, some are 1 X 1 and some are 1 X 2 You also have a 1 X 10 checker board. Your goal is to cover the checkerboard with the tiles so that no two tiles intersect and no tile continues beyond the edge of the board. In how many ways can this be done?

At CenIowa Middle School

there are 1,000 students and 1,000 lockers. The lockers are all down one side of a long hallway and are numbered in the order 1 through 1,000. All lockers are closed.

Math teacher Ang Le has her students count off from 1 to 1,000. Student 1 is sent down the hall with instructions to open every locker. Student 2 is sent down with instructions to change the state of every even locker (close it if open, open it if closed.) Student 3 is sent with instructions to change the state of every locker whose number is a multiple of 3. This continues until all students have been sent. When all 1,000 students have gone, which lockers (if any) are open?

About the artist

Robbie Cropper writes, "Art for me was one of those things that has been a part of my life since I was a child, but was always back burner. It wasn't until recently that I realized that people really enjoy my artwork, and I should do more with it. In the next year I hope to continue to grow as an artist, and put on my first art show."